forked from JuliaLang/julia
-
Notifications
You must be signed in to change notification settings - Fork 0
/
list.j
72 lines (60 loc) · 1.28 KB
/
list.j
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
abstract List{T}
type Nil{T} <: List{T}
end
type Cons{T} <: List{T}
head::T
tail::List{T}
end
cons{T}(h::List{T}, t::List{List{T}}) = Cons{List{T}}(h, t)
cons(x,y) = Cons(x,y)
nil(T) = Nil{T}()
nil() = nil(Any)
head(x::Cons) = x.head
tail(x::Cons) = x.tail
function show{T}(l::List{T})
if isa(l,Nil)
if is(T,Any)
print("nil()")
else
print("nil(")
show(T)
print(")")
end
else
print("list(")
while true
show(head(l))
l = tail(l)
if isa(l,Cons)
print(", ")
else
break
end
end
print(")")
end
end
list() = nil()
list{T}(first::T) = cons(first, nil(T))
list(first, rest...) = cons(first, list(rest...))
length(l::Nil) = 0
length(l::Cons) = 1 + length(tail(l))
map(f, l::Nil) = l
map(f, l::Cons) = cons(f(head(l)), map(f, tail(l)))
copylist(l::Nil) = l
copylist(l::Cons) = cons(head(l), copylist(tail(l)))
function append2(a, b)
if isa(a,Nil)
b
else
cons(head(a), append2(tail(a), b))
end
end
function append{T}(lst::List{T}, lsts...)
n = length(lsts)
l = nil(T)
for i = n:-1:1
l = append2(lsts[i], l)
end
return append2(lst, l)
end